When you're pushing your shopping cart down the supermarket aisle, how do you know which cooking fat to select for heart health? Your choices are endless, from bottles of green olive oil and golden corn oil, to tubs of margarine and sticks of butter. However, some fats are clearly much better for your heart than others.

FATS 101

Dietary fats are a class of nutrients that include specific fatty acids, such as polyunsaturated fat (PUFA), monounsaturated fat (MUFA), saturated fat (SF) and trans fat (TF). Though fat is a very concentrated source of energy--with 9 calories per gram (g), compared to carbohydrates and protein at 4 calories per g--research now indicates that it's not how much fat you eat that's important for heart health--but what type. PUFAs and MUFAs have been linked with a lower risk of cardiovascular disease, because they can decrease your cholesterol levels.

On the contrary, SFs are associated with increased total and "bad" LDL cholesterol and a greater risk of heart disease. Artificially manufactured TF is a fat with no redeeming value; it's been linked with higher LDL and total cholesterol levels and heart disease risk.

IN THE BOTTLE

How do these numbers translate to your favorite fat for cooking? Turn to a liquid vegetable oil with high MUFA content, suggests Janet Bond Brill, Ph.D., R.D., L.D.N., author of "Prevent a Second Heart Attack: 8 Foods, 8 Weeks to Reverse Heart Disease."

"The No. 1 fat in the kitchen is MUFA: extra virgin olive oil in cooking, slathered on veggies and dressing on salads," Brill explains. "MUFAs raise the 'good' HDL cholesterol and lower the 'bad' LDL cholesterol. They stabilize the LDL particles, shielding them from free radical attack, hence preventing oxidation--the initial step in the atherosclerotic process. Extra virgin olive oil is the only oil, because it's a fruit oil and not a seed oil, that's packed with disease-fighting polyphenols--another bonus of making it your main fat."

WHOLE PLANT FATS

Don't forget to turn to nature's original healthy fats--whole plant foods. Nut and seed butters and avocados are particularly rich in MUFAs and PUFAs. Try stirring nut or seed butters, such as peanut butter or tahini (sesame seed paste) into a stir-fry, sauce, vinaigrette or dip. Mix mashed avocado or nut butter into baked goods.

A FAT FOR ALL CULINARY NEEDS

When you don't want the 'olive' taste of olive oil to flavor your foods, try other high-MUFA fats such as canola oil, which offers a very neutral flavor and is great in baking breads, muffins, bars and pancakes. Peanut oil can introduce a nice fat profile into your diet, as well as a mild, peanut flavor which accents Asian dishes.

Try to limit solid fats, such as butter and oleo or stick margarine; butter is high in SF and some stick margarines contain TF. When a firm fat is required for baking, such as in cookies, try soft tub margarine, which contains a better fat profile. Just check to see if partially hydrogenated vegetable oil--code for TF--is listed in the ingredient list. Manufacturers can list TF as "0" on the label, even if it has less than .5 g per serving.

While the type of fat may be the most important factor for heart health, moderation with fats goes a long way. At 120 calories per tablespoon, even olive oil can weigh you down if you glug on too much--and weight gain is not a friend to your heart.

DIETARY GUIDELINES FOR AMERICANS: RECOMMENDATIONS FOR FAT

1. Aim for 20 to 35 percent of your total calories (44 to 78 grams for the average person) from fat. Make the most of those fats: MUFAS, found in avocados, peanut butter, nuts, seeds, olives and vegetable oils; and PUFAS, found in nuts, seeds and vegetable oils.

2. Limit saturated fat -- found in meat, poultry, full-fat dairy, butter and tropical oils like coconut and palm kernel oil -- to 10 percent of total calories (22 grams on average) and even further to 7 percent (16 grams per day on average) for optimal health.